Podcast
Questions and Answers
Which organ primarily synthesizes creatine?
Which organ primarily synthesizes creatine?
- Brain
- Muscle
- Liver (correct)
- Heart
What is the function of creatine in muscle tissue?
What is the function of creatine in muscle tissue?
- It serves as a primary energy source.
- It is reversibly phosphorylated to regenerate ATP. (correct)
- It is a structural protein.
- It acts as a neurotransmitter.
Which amino acid is essential for the synthesis of creatine?
Which amino acid is essential for the synthesis of creatine?
- Tyrosine
- Active methionine (correct)
- Glutamic acid
- Lysine
What does an elevated creatinine level in the plasma indicate?
What does an elevated creatinine level in the plasma indicate?
What is the normal serum creatinine level range for adult males?
What is the normal serum creatinine level range for adult males?
Which isoenzyme of creatine kinase (CK) is primarily found in heart muscle?
Which isoenzyme of creatine kinase (CK) is primarily found in heart muscle?
What happens to creatinine levels in conditions of muscle atrophy?
What happens to creatinine levels in conditions of muscle atrophy?
Where does the process of glycogenesis primarily occur?
Where does the process of glycogenesis primarily occur?
What is the primary fuel source used during the first few seconds of intense muscular contraction?
What is the primary fuel source used during the first few seconds of intense muscular contraction?
Where does the synthesis of creatine phosphate predominantly occur?
Where does the synthesis of creatine phosphate predominantly occur?
Which amino acids are necessary for the synthesis of creatine phosphate?
Which amino acids are necessary for the synthesis of creatine phosphate?
What mechanism is primarily used to replenish ATP during prolonged exercise?
What mechanism is primarily used to replenish ATP during prolonged exercise?
What determines the primary fuel used to support muscle contraction?
What determines the primary fuel used to support muscle contraction?
During a short sprint, which energy system is predominantly utilized?
During a short sprint, which energy system is predominantly utilized?
What is the initial fuel source for muscle contraction during the first few seconds of exercise?
What is the initial fuel source for muscle contraction during the first few seconds of exercise?
What is the role of creatine kinase in the phosphocreatine system?
What is the role of creatine kinase in the phosphocreatine system?
Which of the following describes the anaerobic glycolysis process during exercise?
Which of the following describes the anaerobic glycolysis process during exercise?
Which of the following statements is true regarding the glycolytic system?
Which of the following statements is true regarding the glycolytic system?
What is the role of creatine phosphate in muscle metabolism?
What is the role of creatine phosphate in muscle metabolism?
Which type of phosphorylation occurs in the mitochondria and uses oxygen?
Which type of phosphorylation occurs in the mitochondria and uses oxygen?
Which type of muscle fibers is predominantly active in anaerobic conditions?
Which type of muscle fibers is predominantly active in anaerobic conditions?
Which of the following is a clinical significance of creatinine?
Which of the following is a clinical significance of creatinine?
How is glycogen synthesized in muscle tissues?
How is glycogen synthesized in muscle tissues?
What is the primary reason glycogen is needed in muscles?
What is the primary reason glycogen is needed in muscles?
What covalent change does insulin induce in glycogen phosphorylase?
What covalent change does insulin induce in glycogen phosphorylase?
Which hormone primarily activates glycogen phosphorylase in the liver?
Which hormone primarily activates glycogen phosphorylase in the liver?
What type of glycogen storage disease is associated with a deficiency in glucose-6-phosphatase?
What type of glycogen storage disease is associated with a deficiency in glucose-6-phosphatase?
Which clinical manifestation is NOT associated with Von Gierke's disease?
Which clinical manifestation is NOT associated with Von Gierke's disease?
What is the main enzyme deficient in Pompe disease?
What is the main enzyme deficient in Pompe disease?
Which glycogen storage disease is characterized by failure to thrive?
Which glycogen storage disease is characterized by failure to thrive?
What condition results from a deficiency of muscle glycogen phosphorylase?
What condition results from a deficiency of muscle glycogen phosphorylase?
Which enzyme deficiency is associated with increased hepatic content of glycogen and TAG?
Which enzyme deficiency is associated with increased hepatic content of glycogen and TAG?
What is the glycogen primer composed of?
What is the glycogen primer composed of?
Why is a glycogen primer necessary for glycogenesis?
Why is a glycogen primer necessary for glycogenesis?
What role does glycogenin play when glycogen stores are depleted?
What role does glycogenin play when glycogen stores are depleted?
What is the first step in synthesizing UDP-glucose?
What is the first step in synthesizing UDP-glucose?
Which enzyme is responsible for catalyzing the formation of 1,4 glycosidic bonds in glycogenesis?
Which enzyme is responsible for catalyzing the formation of 1,4 glycosidic bonds in glycogenesis?
What is the significance of branching enzymes during glycogenesis?
What is the significance of branching enzymes during glycogenesis?
What is a key reason for synthesizing glycogen?
What is a key reason for synthesizing glycogen?
How does glycogen storage reduce osmotic effect of glucose?
How does glycogen storage reduce osmotic effect of glucose?
What is the primary role of glucose 6 phosphatase in the liver during glycogenolysis?
What is the primary role of glucose 6 phosphatase in the liver during glycogenolysis?
Which form of glycogen synthase is considered active?
Which form of glycogen synthase is considered active?
What effect do glucagon and epinephrine have on glycogen synthase?
What effect do glucagon and epinephrine have on glycogen synthase?
Which of the following molecules allosterically activates glycogen synthase?
Which of the following molecules allosterically activates glycogen synthase?
What is the function of glycogen phosphorylase in glycogenolysis?
What is the function of glycogen phosphorylase in glycogenolysis?
Which regulatory hormone is known to covalently activate glycogen synthase?
Which regulatory hormone is known to covalently activate glycogen synthase?
How does glucose 6 phosphate influence glycogenolysis?
How does glucose 6 phosphate influence glycogenolysis?
Which of the following is an inactive form of glycogen phosphorylase?
Which of the following is an inactive form of glycogen phosphorylase?
Flashcards
Muscle Fuel Sources
Muscle Fuel Sources
The primary fuel used to support muscle contraction depends on the intensity and duration of physical activity, as well as the types of muscle fibers involved.
Type I Muscle Fibers
Type I Muscle Fibers
Slow twitch muscle fibers are red in color, primarily use aerobic metabolism, and are involved in sustained, low-intensity activities.
Type II Muscle Fibers
Type II Muscle Fibers
Fast twitch muscle fibers are white in color, primarily use anaerobic metabolism, and are involved in quick, high-intensity activities.
ATP Breakdown
ATP Breakdown
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ATP Storage
ATP Storage
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ATP Replenishment Systems
ATP Replenishment Systems
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Where is creatine stored and used?
Where is creatine stored and used?
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What are the amino acids required for creatine synthesis?
What are the amino acids required for creatine synthesis?
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What is creatinine and how is it removed from the body?
What is creatinine and how is it removed from the body?
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How are creatinine levels related to muscle mass?
How are creatinine levels related to muscle mass?
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What does elevated creatinine levels indicate?
What does elevated creatinine levels indicate?
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What is creatine kinase (CK) and its isoenzymes?
What is creatine kinase (CK) and its isoenzymes?
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What is glycogenesis and where does it occur?
What is glycogenesis and where does it occur?
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What is glycogenolysis?
What is glycogenolysis?
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ATP-PC System (Phosphocreatine System)
ATP-PC System (Phosphocreatine System)
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Creatine Phosphate
Creatine Phosphate
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Creatine Phosphate Synthesis
Creatine Phosphate Synthesis
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Glycolytic System
Glycolytic System
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Oxidative Phosphorylation
Oxidative Phosphorylation
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Free Fatty Acids
Free Fatty Acids
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Anaerobic Glycolysis
Anaerobic Glycolysis
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Aerobic Pathway
Aerobic Pathway
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What is a glycogen primer?
What is a glycogen primer?
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How is a new glycogen primer made when glycogen is depleted?
How is a new glycogen primer made when glycogen is depleted?
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How is UDP-glucose synthesized?
How is UDP-glucose synthesized?
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What does glycogen synthase do?
What does glycogen synthase do?
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What does the branching enzyme do?
What does the branching enzyme do?
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What is the significance of glycogenesis?
What is the significance of glycogenesis?
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How does elongation of the glycogen chain occur?
How does elongation of the glycogen chain occur?
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What is glycogenesis?
What is glycogenesis?
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Glycogenolysis (Liver)
Glycogenolysis (Liver)
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Glycogenolysis (Muscle)
Glycogenolysis (Muscle)
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Glycogen Phosphorylase
Glycogen Phosphorylase
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Phosphorylase a
Phosphorylase a
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Phosphorylase b
Phosphorylase b
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Glucagon
Glucagon
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Epinephrine
Epinephrine
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Glycogenesis
Glycogenesis
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Glycogen phosphorylase inhibition by insulin
Glycogen phosphorylase inhibition by insulin
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Glycogen phosphorylase activation by glucagon and epinephrine
Glycogen phosphorylase activation by glucagon and epinephrine
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Glycogen Storage Diseases (Glycogenosis)
Glycogen Storage Diseases (Glycogenosis)
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Von Gierke's Disease (Type I Glycogenosis)
Von Gierke's Disease (Type I Glycogenosis)
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Pompe Disease (Type II Glycogenosis)
Pompe Disease (Type II Glycogenosis)
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Cori Disease (Type III Glycogenosis)
Cori Disease (Type III Glycogenosis)
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Anderson Disease (Type IV Glycogenosis)
Anderson Disease (Type IV Glycogenosis)
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McArdle Disease (Type V Glycogenosis)
McArdle Disease (Type V Glycogenosis)
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Study Notes
Course Information
- Course Title: Muscle Metabolism
- Course Code: BMS 201
- Instructor: Dr. Wael Elayat
- Institution: GALALA UNIVERSITY
- Semester: Spring 2024
Learning Objectives (ILOs)
- Identify that muscle uses 3 energy systems.
- Describe creatine-phosphate energy system.
- Describe synthesis of creatine, creatine-phosphate.
- Describe creatinine, degradation product of creatine and its clinical significance.
- Recognize CK and its isozymes and their clinical significance.
- Describe glycogen.
- Realize the need of muscle for glycogen.
- Describe steps of glycogen synthesis.
- Describe steps of glycogen breakdown.
- Explain regulation of glycogen metabolism: allosteric & hormonal.
- Relate enzymatic defects in glycogen metabolism to metabolic diseases.
Muscle as a Chemical Transducer
- Muscle is the major biochemical transducer converting chemical energy into kinetic/mechanical energy.
- Effective transduction requires a constant supply of chemical energy (e.g., ATP in vertebrates).
Muscle Contraction Fuel Sources
- The primary fuel for muscle contraction depends on the magnitude and duration of exercise, as well as the type of muscle fibers involved.
- Skeletal muscle stores glycogen and some triglycerides.
- Blood glucose and free fatty acids can also be used as fuels.
Muscle Fiber Types
- Type II (fast, glycolytic, white fibers): Predominantly active in anaerobic conditions.
- Type I (slow, oxidative, red fibers): Active in aerobic conditions.
ATP Breakdown in Muscle Contraction
- Muscle contraction relies on ATP breakdown to release free energy, which is coupled to energy requirements for contraction.
- ATP → ADP + Pi + energy → muscle contraction
ATP Storage in Muscle
- The total amount of ATP stored in the body's muscle cells is small (approximately 8 mmol/kg wet weight of muscle).
- This amount is sufficient for maximum contraction for only about 4 seconds.
- Muscles rely on replenishing ATP stores.
Importance of ATP Store
- ATP stores are sufficient for activity for hours.
- Muscle activity depends on ATP for its activity.
ATP Stores and Regeneration
- Initial ATP stores in muscle are depleted within the first 4 seconds of exercise.
- ATP is regenerated via direct phosphorylation with creatine phosphate.
- This phase lasts about 10 seconds
- Anaerobic glycolysis from blood glucose or glycogen provides ATP for 1-2 minutes of prolonged exercise.
- Aerobic pathways using free fatty acids and glucose provide ATP for hours of prolonged exercise.
Mechanisms for ATP Replenishment
- ATP phosphocreatine system (anaerobic)
- Glycolytic system (anaerobic)
- Oxidative phosphorylation (aerobic)
In-class Assessment Question
- Which of the following is a fuel source of energy in the absence of oxygen?
- Glycogen or glucose
Creatine Phosphate Metabolism (Anabolism)
- Creatine phosphate is a high-energy molecule found in muscle.
- It maintains intracellular ATP levels during intense exercise.
- It primarily dominates the first few seconds of intense muscle contractions.
- The synthesis begins in the kidney and continues in the liver.
- Synthesis depends on the health of the kidney and liver.
- The amount of creatine phosphate correlates to muscle mass.
Creatine Phosphate Synthesis Requirement
- Requires three amino acids: Glycine, Arginine (guanido group of arginine), and methionine.
Creatine Phosphate Fate
- Creatine is constantly synthesized daily from the breakdown of creatine and creatine phosphate.
- Creatinine diffuses from muscle to the blood to be excreted by the kidneys.
- Creatinine levels in urine and blood are directly proportional to total creatine phosphate content in the body and muscle mass.
Clinical Significance of Creatine Metabolism
- Creatinine levels in blood and urine are directly proportionate to total creatine phosphate content in the body and muscle mass.
- Creatinine can be used as an indicator of kidney function and muscle mass.
- High creatinine in plasma indicates impaired kidney function.
- Low creatinine levels in blood and urine indicate muscle dystrophy.
- Normal serum creatinine levels are 0.6 - 1.2 mg/dL in adult males, and 0.5 - 1.1 mg/dL in adult females.
CK Isoenzymes
- CK has three isoenzymes (CK-MM, CK-MB, CK-BB) with different distributions in skeletal, heart, and brain muscle, respectively.
- Serum total CK increases with damage to skeletal or cardiac muscles (e.g., myocardial infarction).
Glycogen Metabolism
- Glycogenesis (synthesis of glycogen).
- Definition: the storage of excess glucose in a compact form.
- Site: cytosol of liver and muscle cells.
- Steps: involves the glycogen primer formation and chain elongation from UDP glucose.
Glycogen Synthesis Steps
- Preparation of a substrate: Glycogen primer (a short chain of glucose residues).
- Elongation of glycogen chain: glycogen synthase adds glucose to the primer.
- Branching: Branching enzyme creates branches in the glycogen chain.
Glycogen Breakdown (Glycogenolysis)
- Steps in glycogen breakdown
- Glycogen phosphorylase and debranching enzymes break down glycogen to glucose-1-phosphate.
- Phosphoglucomutase converts Glucose-1-phosphate into Glucose-6-phosphate.
- Glycogen is utilized to supply energy for muscle contraction in muscles.
- In the liver, glucose-6-phosphate is converted to free glucose to maintain blood glucose levels.
Hormonal Regulation of Glycogen Metabolism
- Insulin: primarily promotes glycogen synthesis.
- Glucagon: activates glycogen breakdown.
- Epinephrine: promotes glycogen breakdown, especially in the liver and muscles.
- Adenylate cyclase, cAMP, phosphodiesterase also play a role
Allosteric Regulation of Glycogen Metabolism
- Glucose 6-phosphate and ATP allosterically inhibit glycogen breakdown.
- Increased intracellular Ca²⁺ activates glycogen phosphorylase.
Inborn Errors of Glycogen Metabolism (Glycogen Storage Diseases)
- A group of inherited disorders affecting glycogen metabolism.
- Different types are associated with different deficient enzymes.
References
- Lippincott Illustrated Review Integrated system
- Lippincott Illustrated Review 6th Edition
- Oxford Hand book of Medical Science 2nd Edition
- Clinical Key Student
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Description
Test your understanding of muscle metabolism in this quiz for the BMS 201 course. Explore key concepts like energy systems, the role of glycogen, and the clinical significance of creatine and its derivatives. Understand the biochemical processes that underlie muscle function and its energy requirements.
